Urban ecosystem health assessment and obstacle factor diagnosis using a comprehensive assessment model for Nanjing, China

An urban ecosystem carries the burden of urbanization and records the changes in the ecological environment . A scientific evaluation of the urban ecosystem can effectively assess and identify any system damage and degradation caused by nature or by human activities. In this paper, we construct an urban ecosystem health assessment system on the basis of a pressure–state–response (PSR)/vigor–organization–resilience (VOR) model along with the socioeconomic and remote sensing data related to Nanjing. Meanwhile, the factors hindering the stainable development of the Nanjing ecosystem are discussed. The results indicated that the health of the urban ecosystem in Nanjing is generally on the rise, improving from poor in 2000 to good in 2017; from the results obtained via the PSR model, the state layer continues to decrease, whereas the pressure and response layers continue to increase; the VOR model demonstrated that the urban ecosystem in Nanjing has been relatively stable over the past 20 years, and the obstacle degree model demonstrated that, over the next 10 years, the obstacle factors will be concentrated in the response layer in the early stage and in the pressure layer in the later period, mainly because of the pressure brought about by population growth.